Electromagnetic switch device



y 1939- J. E. FARRELL 2,157,787

ELECTROMAGNETIC SWITCH DEVICE Filed Feb. 5, 1935 2 Sheets-Sheet 1 ulll Him" I ginuenlo'n J. E. FARRCELL 2,157,787

ELECTROMAGNETIC SWITCH DEVICE May 9, 1939.

Filed Feb. 5, 1935 2 Sheets-Sheet 2 w llllllllll W W A W 1 Q? a Q JbseglohEFarrell,

Patented May 9, 1939 i UNITED STATES PATENT OFFICE ELECTROMAGNETIC SWITCH DEVICE Application February 5, 1935, Serial No. 5,140

11 Claims.

This invention relates to a device for protecting electrical service lines, and more particularly to.-a novel construction adapted to be confined in' a small space to reliably and accurately funcvl tion thereby to automatically protect the line in case of an overload occurring therein, and which may be automatically reset when the undesirable condition has been remedied.

A primary object is to provide a device in the form of an electrical connector which may be fitted to an electrical appliance cord thereby to permit of the device being used in connection with conventional or standard receptacles to protect anelectrical appliance plugged into a house convenience outlet.

Another object is to provide an electrical connector of the pin-type including switch means operated electromagnetically upon the occurrence of a short or overload in the line, and which may bemanually reset when the undesirable condition disappears.

A further object is to provide a minimum number of parts, thereby economizing in manufacture and increasing the efliciency of the device in the respect that a minimum number of parts reduces the possibility of malfunctioning.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel features of construction, combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawings and defined in the appended claims.

A preferred and practical embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is a side elevation of the improved connector attached to an electrical appliance 4o cord.

Figure 2 is atop plan view of the device shown in Figure 1.

Figure 3 is a vertical sectional view taken on the line 3-3 of Figure 2 with the switch parts in the position to maintain the circuit closed.

Figure 4 is a view similar to Figure 3 showing theparts of the switch in the position which they assume when the circuit is open.

Figure 5 is a vertical sectional view taken on the line 5-5 of Figure 2.

Figure 6 is a horizontal sectional view taken on the line 6-6 of Figure 3.

Figure 'Iis a side elevation of the switch block.

Figure 8 is an elevation of the opposite side of the switch block shown in Figure 7.

Figure 9 is a bottom plan View of the switch block illustrated in Figure 7.

Figure 10 is a perspective view of the movable switch contact.

Figure 11 is a perspective view of the manually 5; manipulated resetting plunger.

Figure 12 is a perspective view of the insulation barrier or circuit breaker.

Figure 13 is a circuit diagram of the device.

Similar reference characters designate corre- 1n sponding parts throughout the several figures of the drawings.

Referring first to Figure 1, it will be observed that the connector includes in its organization a base A and a cover or cap B which may be re- 15 leasably held to the base by a ring or equivalent means C. The cover B houses a switch block D confined betweenthe base and the cap. With further reference to the cover, it may be pointed out that the same includes a cord receiving open- 20 ing A and a plunger receiving opening A respectively for admitting the wires of an appliance cord E connected to binding terminals on the switch block as will presently appear, and

for receiving the manually manipulated plunger The base A houses an electro-magnet M which includes a core I and a winding 2 having one end connected to the core as indicated at 2 (Figure 4) and the other end connected to a metallic member 2. The base is also provided with pin type conductors 3 and 4, the former being electrically connected with the core I and the latter being electrically connected by the insulated wire 5 or its equivalent with a metallic member 5 Thus, the pin type conductor 4 shunts the magnet winding while the pin type conductor 3 of the other leg of the circuit is in electrical contact with the core I and its winding 2.

The metallic member 5 is intended to engage with an arcuate metal strip carried by the underside of the switch block D and leading to the binding terminal 1 which receives one of the wires T of the cord E.

The metallic element 2 which is connected to the winding 2 is in electrical engagement with the fixed contact 8 of the switch block.

Under normal conditions, the fixed contact 8 is engaged by the movable contact 9 which is a part of a metallic spring frame [0 (Figure 10) having an ofiset perforated ear I I intended to engage with the binding terminal l2 which is in turn electrically connected with the wire 12 of the cord E. Thus, when the fixed contact 8 and mov-r 55- able contact 9 (Figure 3) are in engagement, circuit will be maintained through the connector.

The switch block D is provided with a central passageway for receiving and housing an insulation barrier I3 and the shiftable plunger P, previously referred to. The insulation barrier I3 is provided at its forward end with a bevelled toe I l while its medial portion I5 is recessed to pro vide an opening for receiving a metallic armature-type latch I6 pivotally mounted as at H near the heel of the barrier (Figure 12). The latch I6 is normally urged away from the barrier by a spring Il (Figure 3). The insulation barrier I3 is slidably mounted on the floor of the passage in the switch block and is in a zone overlying the head of the core I of the magnet to be subject to the influence thereof. When attracted by the magnet, the latch I6 is pulled downwardly into the opening I5 against the tension of the spring H.

The plunger P lies at one side of the insulation barrier I3 and frame I8 and is provided with a shoulder I8 for engaging the latch I6. Forwardly of the shoulder I8 the plunger is recessed as at I9 to receive an insulating detent 28 which is pivotally mounted in the recesses as indicated at 2I and is normally pushed in one direction, that is, toward the frame, by a leaf spring 22 (see Figure 11).

Both the plunger P and insulation barrier I3 are spring urged in one direction. To that end, the arms of a single spring may be used. Referring to Figures 6, '7 and 10, it may be observed that the frame I 8 may be provided with an opening IU for receiving the medial portion of a spring whose lower arm 23 passes beneath the frame and around the lower head of an eyelet or equivalent fastening 24, thereby to engage the rear side of the insulation barrier I3 as indicated at 23 in Figure 7 or at any other convenient point. The upper arm 25 of the spring passes over the upper side of the frame I8 and beneath the upper head of the fastening 24 thereby to engage the rear end of the plunger P, for example, as indicated at 25 (Figure 7). Therefore, both the insulation barrier and plunger P are urged in the same direction by the spring arms referred to and move under the force of these springs when free to do so.

When the device is set for normal operation so that current may flow through the connector, the parts may assume the position shown in Figure 3. From the latter, it will be observed that the fixed and movable contacts 8 and 9 are in engagement and that the toe I4 of the insulation barrier is held retracted because the end of the latch I6 is in engagement with the shoulder I8 due to spring I'I. Also, the detent 28 is engaged with the rear side of the contact 9 on the frame I0 due to the fact that the spring 22 urges the detent downwardly in the slot I9 of the plunger. Upon the occurrence of an overload in the line, the magnet will function to pull the latch I6 against the tension of the spring H whereupon the insulation barrier I3 will be free to snap forward under the force of the spring arm 23. As the force of the spring projects the barrier forward, the toe I4 thereof kicks the detent 28 upwardly, thereby releasing the plunger from engagement with the frame and the. continued movement of the barrier I3 forwardly will cause the toe I4 thereof to lift the movable contact 9 so that the barrier will be pushed between the fixed contact 8 and movable contact 9 and thus break the circuit.

If the overload or other undesirable condition in the line is immediately removed, or is merely momentary, the plunger P may be pushed inwardly to reset the parts. When the magnet is deenergized, the spring II will push the latch I6 away from the barrier. As the plunger is pushed inwardly, the shoulder I8 will pick up or engage the latch and drag the barrier I3 backwardly. As soon as the plunger P is pushed inwardly a sufiicient distance against the tension of the spring arm 25, the spring 22 will force the detent 28 into engagement with the end of the movable contact frame and the device will be reset because contacts 8 and 9 will again be brought together.

Assuming that the overload or undesirable condition persists in the line and it is attempted to manually reset the switch through the medium of the plunger P, it may be pointed out that the plunger will at first pick up the latch I6 through the medium of the shoulder I8 and move the barrier backwardly until the contacts 8 and 9 reengage. Since the contacts 8 and 9 will re-engage before the detent 20 is pushed into locking position with respect to the frame II], it will be apparent that the circuit will again be re-established before the detent can permanently reset the parts. Consequently, the magnet will pull the armature type latch I6 downwardly away from the shoulder I8 so that the detent 28 cannot engage with the contact end 9 of the frame, and, immediately the barrier I3 will be snapped back between the contacts 8 and 9 to break the circuit. As long as the undesirable condition persists in the line, it will be apparent that the detent 20 cannot lock or hold the barrier I3 in its fully retracted position. Therefore, the device cannot be reset as long as the undesirable condition obtains in the line. The barrier is not subject to manual control while the undesirable condition obtains in the line for complete resetting purposes.

The present connector is intended to be used with an appliance cord and to that end is equipped with the pin type connectors 3 and 4 for entering the openings of the usual pin type convenience outlet commonly used in house wiring. In the event that a short or overload occurs either in the service line or the appliance connected to the cord, the electro-magnet will immediately function to break the circuit automatically. It may be reset when the undesirable condition has been removed, and it cannot be reset as long as the short or overload persists in either the service line or the appliance cord line, as previously explained.

I claim:

1. A combined overload cut-out and electrical connector of the cord and plug type for establishing a circuit line from a service outlet to a current consuming device, including, a connector body housing a normally closed switch device and electro-magnetic means responsive to overload in the line for opening the normally closed switch device, means accessible from the exterior of the body for manually re-closing said switch, and separate pin type conductors carried by the base and respectively in circuit with the electro-magnet and the switch device.

2. An overload cut-out and electrical connector of the cord and. plug type for establishing a circuit line from a service outlet to a current consuming device comprising, in combination, a housing including cap and base sections, a switch device in the cap including fixed and movable contacts, line wire binding terminals for the switch device, normally restrained insulation meansifor separating the fixed and movable contacts of the switch device, an electro-magnet in the base for controlling the release of said insulation means, means for manually resetting the said insulation means, and'a pair of pin type conductors on the base section, one of said conductors being electrically connected to the'electro-magnet and the fixed contact of the switch and the other of said conductors being electrically connected with one of the said binding terminals of the switch and also with the movable contact thereof.

3. A combined overload cut-out and electrical connector of the cord and'plug type for establishing a circuit line from a service outlet to a current consuming device, including, a connector body comprising normally coupled sections one of which houses a switch device having normally closed' switch contacts and a spring urged insulation member, electro-magnetic means within the other section of the body and responsive to overload in the line for automatically opening the normally closed switch device and simultaneously interposing said insulation member between the disconnected contacts, means for manually shifting the insulation member from between the disconnected contacts to reclose the same and reset the insulation member, and separate pin type conductors carried by the base and respectively in circuit with the electro-magnet and the switch device.

4. An electrical connector including a base, a cover detachably fitted to the base and having a plunger opening; a switch block housed between the cover and the base; binding terminals on the block; pin type conductors on the base, one of which is electrically connected with one of the binding terminals; an electro-magnet in the base including a core connected to the other pin-type conductor, said electro-magnet including a winding having one end connected to the core; a fixed contact on the block in conducting relation to the other end of the magnet winding; a movable contact on the block normally engaging said fixed contact and electrically connected with the other of said binding terminals; a spring actuated insulating member adapted to be thrust between said fixed and movable contacts; an armaturetype latch on the insulation member adapted to be actuated in one direction by the electro-magnet; a spring actuated plunger having a portion operating through said plunger opening of the cover; and means on the plunger for holding said insulation member normally retracted from the fixed and movable contacts.

5. An electrical connector for establishing an electrical circuit between an appliance and a service outlet, including, a base, a cover detachably fitted to the base and having a wire receiving opening and a plunger receiving opening, a switch block housed between the cover and the base, an electro-magnet in the base, binding terminals on the switch block for receiving wires passing through the wire receiving opening of the cover, switch means carried by the switch block and located therein between the binding terminals, said switch means including means automatically responsive to the electro-magnet and manually operable means projecting through the plunger opening, said manually operable means adapted to reset said automatic means when undesirable conditions have disappeared from the line.

6. An electrical connector for establishing an electrical circuit between an appliance and a service outlet, including, a base having an electro-magnet therein, a cover detachably fitted to the base and having a central cord receiving opening and a lateral plunger receiving opening, a switch block housed between the cover and the base, binding terminals on the block for receiving wires of a cord led in the cover through said cord opening therein, switch means mounted in the block and including a pair of relatively slidable members which are normally interlocked and one of which carries an armature type latch responsive to the electrc-magnet and the'other of which has a portion projecting through said plunger opening for manual manipulation, said last mentioned member carrying therewith a detent for normally engaging with the said first mentioned slidable member.

7. An electrical connector was establishing an electrical circuit between an appliance cord and a service outlet, including, a base having an electro-magnet therein responsive to an electrical impulse in one leg of the circuit, a cover detachably fitted to the base and having a cord receiving opening and a plunger receiving opening, switch means housed between the cover and the base and including binding terminals for receiving wires of a cord led in through said cord receiving opening of the cover, fixed and movable switch contacts, and a pair of relatively shiftable insulation members disposed one adjacent the other, one of said members carrying an armature type latch responsive to the electro-magnet, and urged in one direction by a spring to be thrust between said fixed and movable contacts when the armature type latch is attracted by the magnet, and the other of said members carrying therewith a detent for engaging with a portion of the movable contact when the same engages with the fixed contact of the switch, said last mentioned member having a portion extending through the plunger opening of the cover.

8. An electrical connector for establishing an electrical circuit between an appliance cord and a service outlet, including; a base having therein an electro-magnet including a core and winding, and also having means for connecting with service outlet terminals; a cover detachably fitted to the base and having a cord receiving opening and a plunger receiving opening; switch means housed between the cover and the base and including binding terminals adapted to receive wires from the cord led in through said cord receiving opening of the cover; a fixed contact electrically connected to the winding of the electro-magnet which is in one leg of the circuit; a movable contact electrically connected with one of the binding terminals which is also in the same leg of the circuit, said movable contact normally engaging the fixed contact; and a pair of spring pressed relatively slidable insulation members, one of which carries an armature-type latch adapted to be attracted by the electro-magnet to permit said member to be projected between the fixed and movable contacts to interrupt the circuit, and the other of which members has a portion projecting through the plunger opening of the cover for manual manipulation, said last mentioned member carrying a detent therewith for normally engaging said movable contact when it is engaged with the fixed contact to maintain both of said members in normal circuit establishing position.

9. In a device of the class described, a fixed contact and a movable contact, a spring tensioned insulating member adapted to be thrust between said fixed and movable contacts, an armature- 78 type latch carried by said member and urged in one direction by a spring, and a resetting plunger having a shoulder adapted to be engaged by said armature type latch and also having a spring actuated detent adapted to engage with the said movable contact when the same is in circuit maintaining relation with the fixed contact.

10. In a device of the class described, an electro-magnetically operated switch including a switch block having a fixed contact and a movable contact, line wire binding terminals on the block, one of said terminals being electrically connected with the movable contact, a spring tensioned insulation member slidably guided in the block and adapted to be projected between the fixed and movable contacts, an armature-type latch carried by said insulation member, and a spring tensioned resetting member having means for engaging said armature-type latch and also having means for engaging with the movable contact to maintain the two members normally interlocked.

11. In a device of the class described, an electro-magnetically operated switch including a switch block having a fixed contact and a movable contact, line wire binding terminals on the block, one of said terminals being electrically connected with the movable contact, a spring tensioned insulation member slidably guided in the block and adapted to be projected between the fixed and movable contacts, an armature-type latch carried by said insulation member, and a spring tensioned resetting member having a shoulder for engaging said latch and also having a movable detent adapted to drop behind the movable contact to maintain the two members in a retracted position with respect to said contacts.

JOSEPH E. FARRELL. 

